Centrifugal motor switch



April 28, I925. 1,535,766

J R. COCK CENTRIFUGAL MOTOR SWITCH Filed Au. 5, 1922 2 Sheets-Sheet l g t I In \w April 28, 1925.

, 1,535,766 J. R. cooK CENTRIFUGAL MOTOR SWITCH Filed Aug. 5,- 1922 2 Sheets-$heet 2 Patented Apr. 28,1925. P

UNITED STATES:

"1,535,166 PATENT OFFICE.

JOEL n. ooox, or naxnwoon, omo, assren'on' 'ro rim nouns'nc nLEcmc comrnmr, or CLEVELAND, omo, A coarona'rron or one.

CENTRIFUGAL MOTOR SWITCH.

Application mea- August 5, 1922. Serial li o. 579,789.

To all whom it may concern:

Be it known that I, JonL R. 0001:, a citizen of the United- States, residing at Lakewood, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Centrifugal Motor Switches, of which the following is a full, clear, and exact description, reference being had to .the accompanying drawings.

This invention -is directed to improvements in centrifugal switches such as are used in small induction motors for cutting out an auxiliary; set of field windings which are used for starting purposes only.

The general object of the present invention is the provision of a switch mechanism having pivotally'mounted contact elements supported on the rotor of the motor which ary contacts secure 'to the motor frame during the starting and prelimina period in which the'increase in the spec of the of the speed of the motor. The elements acted upon'by centrifugal force are-of a simple design and formed of compressed metal.

A more specific object of the present invention is the provision of a centrifugal switch wherein a plurality of rotatable contact arms are provided which are pivotally secured to a support; the contact arms being formed of comparatively thin metal 'butshaped in such a manner as to provide in effect unusually wide bearing portions to insure a uniform and simultaneous movement of all of the arms when the rotor has reached a predetermined speed, the whole being so designed as to be almost entirely manufactured in high production by stamping and pressing operations and be capab e of great uniformity for convenience in assembling.

A further object is the provision of rotatable contact elements havin the foremembers connected to the arms and the support, may normally maintain the arms in an inward contacting position, but which,

are maintained in engagement with station of the switch mechanism after the switch going characteristics and in ad ition there-.

' when swung outwardly by centrifugal force,

cause a decrease in that component of force of the spring members, which is directed to maintaining the arms in an inward position, thus causing the arms to close inwardly at a speed of rotation considerably less than the speed at which they are swung. outwardlg by centrifugal force.

A urther object is the provision of a centrifugal switch mechanism which will effectively fulfill the foregoing objects and which may be-so constructed as to occupy a minimum of space within the motor frame.

Other ob'ects will be apparent from the following escription taken in connection with the accom anying drawings, which illustrate an em odiment of my invention: the essential objects will be summariz ed in the claims. v

In the drawings, Fig. lis a side elevation of the motor with a portion thereof shown in cross section to illustrate the relative position of the switch mechanism; Fig. 2 is a cross section of the switch mechanism taken along'the line 22 of Fig. 1, showing the switch mechanism in a starting or closed condition; Fig.v 3 is a similar view showing the relation "of the movable parts has been'opene'd by centrifugal force; Fig. 4 is a side view of the movable parts of the switch, and Fig. 5 is a perspective view of one of the contacting elements of the switch.

1 indicates a motor housing having an integral base 2 and supporting the field structure 3. The frame members 4 are sestitutes a support for non-rotatable segments 8, properly flanged to permit the securing thereof to the disc member; (3. To these non-rotatable segments are connected lead wires 11 and 12. which comprise a part of the circuit of the starting wmdin S as shown in Fig. 2. This circuit may. e attached to the field circuit 14 in such 'a' manner as tov connect the field windings F, through the switch when-closed in parallel with; the starting windings S.

The rotatable elements of the switch 110 ber 18 mounted on one end of the rotor 19' and secured thereto by screw members 40' mechanism comprise a metallic disc mem- .Spring members 25 are connected to outwardly extending lugs 26 formed about the perimeter of the disc member 18 and to'the contacting arms 20 in a manner to be presently described. It will be noted that these lugsnlikewise comprise stops for positively limiting the outward swing of the contact arms 20. I

The. contact 'arms 20 are preferably stamped, as illustrated in Fig. 5, with the contact portion 21 extending from'thearm portion substantially at rightangles thereto, and formed adjacent the free end of the arm. The bearing portion of the arm may comprise a U-shaped end with'aligned openings 28 and 29 formed in the legs 20 and 30 thereof whereby a double bearing contact is obtained when the contact arm is mounted on the pin members 23. The distance betweenth'elegs of the U portion of the arm may be such as to'provide a sufficient span between'the bearing portions of *the'arm" when mounted on the pin, to prevent-wobb1ing of the arm as it is. swung about-the center of the pin by centrifugal force. By this bearing arrangementl gain the advantages, of a solid bearing portion having a bore and opening formed in the solid metal equal to the overall distance between the bearing portions of the present arm, and at the same time having less friction, lessweight, and Irefi'ect aneconomy of .materialand in the steps of construction.

Informing thebearing end of the contact arm in the manner described, a portion 31 which bridges or spans two bearing portions of the arm may have an opening 32 7 formed therein intermediate of these bearinglportions. When the contact arm is mounted on the pins 23 this opening will be in alignment with an opening 26 formed in an extended portionof the lug 26 and;

the ends of the spring members 25 may be connected or hooked into the respective openings whereby the center line ofthe spring will be parallel to the supporting disc '18. To facilitate the assembling of the end member 4 when the stationary segments 8 are secured thereto, the contacting portion of the arms '20 may have the outer ends against which. the arms are held in an in-v ward position by the spring 'members 25 when the segments 8 are not in assembled relation to the cont-act arms but still sufliciently separated'to allow convenient insertion of the segments by simply sliding one over the other.

It will be noted that the efiective component pull ofthe spring on thelever is decreased as the arms swing from the contacting position to the open position. The result of this change in the component of spring pull upon the arms is that the switch 1 mechanism opens at a high speed which is predetermined by the size of the springs used but the contact arms will not be brought to a closed or contacting position until the rotation of the motor armature is considerably below the speed at which the contact arms moved outwardly. The period in which thecontact arms is rubbing upon the stationary segment is therebygreatly I reduced.

From the foregoing descriptionilit; twill* be seen that I 'have provided aiivery simple, l I

yet efiicient centrifugal.switchfconstruction-1 wherein a plurality of arms of mesmeshape and. formed of pressed metal are mounted upon a pressed gmetal disc; the

contact portions ofthe arms being formed to provide extraordinary contact or running surfaces yieldablybearing upon stationary segments which are also formed of pressed, metal. bing part being sufiicient to allow; for considerable weight, thus preventing the rapid deterioration of the switch, due to arcing and 'corroding of the contacting parts.

I claim I 1. In a centrifugal switch, the combination of a rotary support, astationarycontact, a plurality of contact arms pivotally mounted upon the support and spaced equiangularly thereon, the pivotal center of the arms'being spaced at equal radial distances from the center of rotation of theswitch, said contact arms having U-shaped bearing portions comprising thepi'votal mountings thereof and spring members connectedto .said arms intermediate the legs of the U- The thickness of the rub- 2. In a centrifugal switch, the combina tion of a rotary support, a stationary contact, a plurality of contact arms pivotally mounted upon the support and spaced equiangularly thereon, said contact arms having parallel portions spaced apart and spring members connected to said arms intermediate said parallel portions and connected to lugs formed on said rotary support.

3. In an electric motor, a centrifugal switch having a rotary supportinounted on one end of the rotor and a stationary contact segment mounted on an end housing member of the motor, said centrifugal switch having a plurality of coacting contact arms pivotally mounted upon said rotary support, spring members connected to the ends of the contact arms and to the rotary support, whereby the free ends of the contact arms are maintained in contact with said stationary segments, said contact arms having the contacting portions thereof flared outwardly, and said contact segments having the ends thereof flared inwardly whereby the end housing member of the motor frame may be assembled upon the frame with the stationary segments mounted thereon, the flared portions of the respective switch members contacting with the flared portions of the segments in such a manner as to cause an outward movement of the contact arms when the end member is being attached to the motor frame.

4. In a centrifugal switch, the combination of a rotary support, stationary contacts, and a plurality of coacting contacting arms pivotally mounted on the rotary support and proportioned relative to the pivotal connection to swing outwardly under the influence of centrifugal force at a predetermined speed of the rotor, said contact arms being formed of pressed metal with U-shaped portions having the legs thereof perforated to provide a pivotal connection with the support, pivot pins passing through said openings and spring members connected to the arms intermediate said legs.

5. In a centrifugal switch, the combination of a rotary support, a stationary contact, a plurality of contact arms formed of pressed metal with arcuate brush portions engaging said stationary contact, each arm being independent of the other and having parallel extending portions, pivot pins passing through said parallel portions of the arms and rigid with the support, resilient means connected to said arms and the support, the connecting point of the resilient means with the arm being located relative to the pivotal axes thereof in such a manner that the component force exerted thereby upon the arms to maintain the arms inwardly will be decreased as the arm is swung outwardly under the influence of centrifugal force.

6. In a centrifugal switch, the combination of a rotary support comprising an apertured disk provided with a plurality of equi-angularly spaced lugs formed about the outer perimeter thereof and a plurality of lugs formed about the inner perimeter thereof, a plurality of pressed metal contactarms, a stationary contact comprising two elements in the nature of a split flanged cylinder, resilient means normally maintaining the arms in operative relation to said stationary contact, said inner lugs serving to limit the inward movement of the arms in the absence of the stationary contacts and the outer lugs serving to limit the outward movement of the arms when swung outwardly by centrifugal force.

In testimony whereof, I hereunto affix my signature.

JOEL R. 000K. 

